2F5 Flashcards
hemoconcentration definition
use of membrane to concentrate blood components by removing plasma water
what is hemoconcentration driven by?
convection and transmembrane pressure
hemofiltration definition
use of membrane in conjunction with fluid replacement to reduce the concentration of water-soluble components of plasma
what is hemofiltration driven by?
convection and transmembrane pressure gradient between blood and ultra filtrate side of membrane
hemodialysis definition
use of membrane in conjunction with fluid dialysate to remove water-soluble components from plasma
what is hemodialysis driven by?
diffusion gradient across the membrane
ultrafiltration definition
generic term for the removal of plasma water and its soluble components from blood via convection
what is “ultrafiltrate”
fluid removed
what is hemoconcentration used for on CPB
to effective remove excess fluid in the ECC
what does hemoconcentration help control?
circulating volume and HCT
hemoconcentration helps maintain ____ pressure by….
helps maintain oncotic pressure by retaining plasma proteins and removing excess plasma water
what is Pre-Buf?
pre-CPB ultrafiltration of pump prime
addition of banked blood to prime
when would blood to prime in Pre-Buf be harmful?
to neonate patients who blood volume less than prime volume
how is primed circuit blood delivered?
under pressure into the ultrafilter
how is ultra filtrate handled to maintain operating level in reservoir?
removal balanced with addition of balanced electrolyte solution
what is conventional ultrafiltration (CUF)?
means of managing CPB circuit volume and increasing hematocrit without bank blood
how is CUF set up during CPB
receive blood from high-pressure arterial side of circuit and return blood to low-pressure venous side of circuit
what is a consideration when using conventional ultrafiltration?
must have adequate volume in venous reservoir to safely remove ultra filtrate and maintain optimal flows during CPB
when is CUF used?
- after aortic declamp
- during rewarming
- UF in parallel with CPB
- Inlet after the oxygenator
- UF blood return into venous reservoir
what are the advantages of CUF
- does not delay surgical times
- removes UF during highest mediator production phase
what are the disadvantages of CUF
it might quickly empty reservoir volume
what are the continuous ultrafiltration replacement
ZBUF
HVUF
DUF
what is ZBUF
zero balance
what is HVUF
high volume
what is DUF
dilutional
what is the goal of continuous ultrafiltration replacement?
goal to remove 3-6 L of ultra filtrate
when do you ultrafiltrate?
at 200 ml/min during rewarming
what is the post CPB ultrafiltration?
MUF
what is MUF used for?
technique developed to reduce total body water and tissue edema that results after pediatric CPB
what is AV-MUF
blood from aorta pumped through filter returned to RA
what are alternative MUF configurations? .
VV MUF
VA MUF
considerations for MUF
- delays protamine administration
- possible air entrapment in AV MUF
what are the advantages of MUF
significantly high efficiency
what are the disadvantages of MUF
- cumbersome procedure
- patient cooling
- hemodynamic instability
potential role of UF in post CPB
capillary leak syndrome
what is possibly removed in post CPB UF
inflammation mediators
-C3a, C5a, IL-6a, IL-8a, TNF, MDF, ET-1
what else could possibly result from UF in post CPB
total body water reduction
- tissue edema decrease
- hematocrit increase
- coagulation factors concentration
- decreased need of hemoderivates
UF on left ventricular function
- myocardial edema decrease
- DO2 increase
- left ventricular compliance increase
- systolic and diastolic function improvement
what is monitored for hemodialysis during CPB
monitoring of patient’s blood electrolytes and metabolites
monitoring of arterial shunt created for dialysis as to not reduce actual blood flow to patient
what is circuit salvage post CPB
preserves plasma proteins and coagulation factors
-heparin will be in rein fusion product so protamine reversal doses must be considered
what is sieving coefficient?
defines its movement across a membrane
as value of S approaches 1.0, its ability to diffuse through membrane increases
sieving coefficient equation
S = drug concentration in ultrafiltrate/ drug at filter inlet
